SharePoint has designed a structured metadata model to use so that you can map the necessary operations and fields for your business data in a way that SharePoint understands and does not require custom code. You will need to know what data you would like to make available from your application and how to access your data and application.
You can use the BDC to display data from database applications or applications that allow Web service access to the data.
The structure of the metadata file that you will design for each data source follows the same hierarchy for every application. An application is a definition of a data source and the connection method used; each application can have multiple entities and associations, as described in subsequent sections. There is only one application defined in every metadata file, and it is defined using these tags:
LobSystem: This is the root-node container for metadata about your application. It contains all objects for that application, and there is only one LobSystem per application or XML file.
LobSystemInstance: This object contains the authentication and connection string information for your application, and there is only one LobSystemInstance per LOBSystem. Available authentication modes are:
PassThrough: This authentication method passes the user’s credentials to the database for authentication.
RevertToSelf: In this authentication scenario, IIS impersonates the Windows credentials ...